S H 

.V7 DEVICES FOR USE IN FISH HATCHERIES 
AND AQUARIA ^ ^ ^ ^ .< 

From BUIvIvETiN OF THE BUREAU OF FISHERIES, Volume XXVIII, 1908 
Proceedings of the Fourth International Fishery Congress : : Washington, npoS 



WASHINGTON :::::: GOVERNMENT PRINTING OFFICE :::..-: 1910 




(lass C^Hi^^ 
Book Kl 



DEVICES FOR USE IN FISH HATCHERIES 
AND AQUARIA ^ ^ ^ .^ ^ 

From BULLETIN OF THE BUREAU OF FISHERIES, Volume XXVIII, 190S 
Proceel^igs of the Foiirlk Infcniational Fishery Congress : : Washitigtoii, igo8 




^j^^^CJ-^T 



WASHINGTON :::::: GOVERNMENT PRINTING OFFICE 



^ 






BUREAU OF FISHERIES DOCUMENT NO. 703 
Issued April, 1910 






r 






DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA 

By Eugene Vincent 

Fish Culiurist, Aquarium oj the Trocadcro, Paris 

J* 

Designs presented before the Fourth International Fishery Congress 
held at Washington, U. S. A., September 22 to 26, 1908 



CONTENTS. 

Page. 

Artificial pond with siphoid outlet for regulation of height of water 1027 

A siphoid outlet for hatching and rearing troughs '°29 

A suction apparatus for cleaning hatching and rearing troughs 1030 

A cleaning device for ponds or aquaria '°3^ 

Oxygenation and vacuum-producing apparatus '°33 

Scraper for preparing fish food ' 34 

1026 



DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



By EUGENE VINCENT, 
Fish Cullurist, Aquarium of tlie Trocadero, Paris. 



[Translated from the French] 
ARTIFICIAL POND WITH SIPHOID OUTLET FOR REGULATION OF HEIGHT OF WATER. 

This pond is made of cement, the bottom having a layer 0.05 meter in 
thickness and a Hning of 0.02 meter, the sides being 0.08 meter in thickness. 
The dimensions are 12 to 15 me- 
ters by 3 meters, with any de- 
sired depth, and the ends are 
rounded. Crosswise the bottom 
slopes from the middle upward 
at the degree of 0.05 meter per 
meter, which equals 0.75 meter 
for a side of 1. 50 meter. With this 
slope the pond may be cleaned 
by simply sweeping toward the 
center or by means of a few 
buckets of water thrown against 
the sides. It is fed by one or 
more troughs which empty into it 
with a stream of 0.20. 

The pond must be level in 
lengthwise direction, in order to 
preclude danger of leaving any 
dry area below a given height. 
In the middle of the bottom of 
the pond, beginning at the intake 
end and terminating in a circular 
basin which occupies the opposite end, is a gutter at least 0.50 meter in width 
and 0.12 to 0.15 meter in depth. The circular basin is from 1.50 to 1.80 meters 
in diameter, and 0.20 to 0.30 meter in depth. With the gutter it serves to hold 




ul pniid with siphoid outlet. 



I028 BULLETIN OF THE BUREAU OF FISHERIES. 

the fish when the water is drawn out of the rest of the pond for cleaning. 
The cleaning process itself is simplified, since a man may enter for the pur- 
pose and walk about on the bottom of the pond. 

So far the pond is not provided with any outlet. In the wall opposite the 
intake, 0.15 or 0.20 meter above the gutter in the bottom of the pond, is an 
aperture 0.50 to 0.60 meter square, covered with wire netting. This, however, is 
not an outlet but an overflow. The outlet proper is in the bottom of the large 
circular basin and consists first of an opening 0.60 meter square and o.io too. 12 
meter deep. Into this square is set a wooden box with a wire mesh bottom, 
and this box, filled with coarse gravel, rests upon an iron grating 0.60 by 0.60 
meter. Below the grating is a circular basin 0.50 meter in diameter and o.i 5 
meter in depth, with an opening in the center which leads into an outflow pipe. 

The outlet provided, the regulation of the water level in the pond remains 
to be accomplished. This is done by carrying the outflow into a tank or other 
receptacle outside the pond, in which any desired level may be maintained by 
regulation of its overflow. The latter is controlled by a board wall or dam con- 
structed of removable sections. 

In addition to the convenience of this construction in regulating the height 
of water in the ponds, there is afforded every protection against loss of the small 
fish, since the water in leaving must pass through gravel the size of hazel nuts ; 
the cleaning of the pond may be accomplished without injury or shock to the 
fish; all impurities fall into the gutter and are carried off through the circular 
basin, while the fish, seeking the incoming current, are in the upper strata of 
water and away from all such impurities as do not pass through the screened 
outlet; the fish are provided with desirable currents derived from the action of 
the siphon, and the pond is continuously self -cleaning. When the fish are 
larger the gravel may be removed, and still later the screen itself may be 
discarded. 

Fish culturists will appreciate the importance of perfect control of their 
rearing ponds. A construction such as this described is possible wherever there 
is a fall of at least i meter in the water supply, since it is not necessary to take 
the siphon apparatus into account. There is but one thing absolutely necessarj^ 
to provide against — namely, the possibility of emptying the pond entirely, 
down to the screen with the gravel. It is of little importance that the outflow 
pipe is not emptied ; the water will always flow off, on account of the difference 
of level. 

The design has been adopted with satisfactory results in several fish culture 
establishments in France. 



DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



1029 



A SIPHOID OUTLET FOR HATCHING AND REARING TROUGHS. 

The various systems of outlet in most fish-cultural equipment are defective 
in several ways, as I have had occasion to observe on visits to different estab- 
lishments. The young fish escape in the outflow, perhaps, due to its faulty 
construction or installation ; many of them are caught in the perforations of the 
sheet-iron cap and die there; many others are killed or injured by the fingers 
that try to rescue them ; overflows are caused by the clogging of the perforations ; 
the water is not thoroughly re- 
newed and the trough becomes 
infected with germs of disease. 
All this is too familiar to need 
to be dwelt upon. I have sought 
to overcome various difficulties by 
the following device. 

I have provided a large cylin- 
drical wire screen or cage, which is 
set over the outlet and incloses the 
outlet apparatus which I shall de- 
scribe. The large surface of the 
screen gives free course to the 
water without attracting the young 
fish and thus becoming a means 
of their destruction. 

In the daily procedure of 
changing the water in the rearing 
troughs, I desire to be able to 
lower the level to a given point 
without the necessity of losing 
time waiting beside the trough. 
To accomplish this I have made, 
first, for the orifice in the bottom 
of the trough, a water-tight collar 
of two pieces screwed together 
with a leather washer between. The lower piece is supplied with lugs extend- 
ing downward, and into this collar is inserted a tube, making an ordinary 
standpipe. With this form of outlet, however, the water is renewed only at 
the surface, the bottom water, with remnants of food, refuse substances, etc., 
being left unchanged. I have accordingly elaborated the standpipe into a form 
which constitutes an unfailing cleaning device. It carries off all the solid matter 




siphoid outlet for hatching and rearing troughs 



1030 BULLETIN OF THE BUREAU OF FISHERIES. 

that passes through the screen, and affords a desired current for the young fish, 
which do not Hke to be inactive. 

For this purpose a second slightly larger tube is slipped over the stand- 
pipe and, by means of a clamp collar supported on three legs, is held with its 
lower end just above the bottom. The current thus produced can be regulated, 
greater force being obtained when desired by lowering the outer tube and thus 
preventing the full outflow of water. This raises the level in the trough, and 
the difference between the level in the trough and the stream which can escape — 
namely, the height of the inner standpipe — makes the pressure to force the 
water up from the bottom and carry with it the refuse matter in the trough. 
It is not in a trough such as this that there will be ill-smelling bottom water. 

The apparatus does not, as one might think, act merely as do communi- 
cating vessels. With a flow of 2 to 3 liters per minute I obtain a diiference of 
level of 3 to 4 centimeters, according to the elevation of the outer tube. By 
regulation of this tube, which is very simple, both surface and bottom water 
will be renewed. If only the lower water were emptied an oily layer would 
form at the surface and act as an insulator between the air and the water. 

As the aquarium of the Trocadero is supplied by sluices, in the flow of 
which there might be the same fluctuations as in the river, I have provided 
an emergency overflow to balance any sudden rush of water. 

When it is desired to remove some of the fish from the trough the whole 
apparatus may be removed, the mouth of the outlet in the bottom of the trough 
being closed with an ordinary cap or plug. 

A SUCTION APPARATUS FOR CLEANING HATCHING AND REARING TROUGHS. 

This device is designed for use in the removal of dead eggs or fry, remnants 
of food, or any undesirable substance that may be found in the troughs. The 
use of the usual metal or wooden tweezers, or perhaps long pins, too often 
causes the eggs to burst, thus spreading infection from their decomposed 
contents. Little glass pipettes are used, taking one egg at a time. But this 
often escapes and, falling to the bottom of the trays, is left to give rise to 
Saprolegnia. 

To meet these difficulties I have used a pipette with a rubber bulb attached. 
The tubes vary in diameter, according to the sizes of the different species of 
eggs, and are 0.25 meter long, being slightly bent at the entrance to the bulb. 
At the outer end is a ring of blue glass to guide the eye of the operator. With 
the aid of this form of pipette 15 or 20 eggs may be taken up to be thrown out 
of the trough at one motion of the operator. 

Upon this appliance as a basis I subsequently devised a second means of 
cleaning by combination with the siphon principle. The later apparatus 



DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



103I 



consists of a long rubber tube attached, with metal handle and connections, 
to a blue-tipped pipette on one side and to a rubber bulb on the other. The 
bulb normally receives its air supply through a small rubber tube which is 
connected with a metal piston valve inserted in the large tube some 0.60 meter 
below the bulb. An auxiliary air valve in the handle is controlled by a little 
piston within reach of the index finger of the right hand. 

To use this apparatus have the lower end of the large tube and also the 
lower piston valve below the water level 
existing in the trough. Squeeze the bulb 
with the right hand, press the lower piston 
with the left, and then, putting the end of 
the glass tube in the water, release the 
bulb. Then release the piston and the 
siphon will have started. The glass tube 
may be directed at will. If the suction 
is too strong it may be regulated by the 
piston in the left hand. 

Should a good egg be picked up by 
mistake it may be readily replaced with- 
out waiting for it to discharge at the lower 
end of the rubber tube. Stop the flow of 
water by closing the lower piston with the 
left hand ; then press the bulb to expel the 
air from the small tube upward into the 
larger, the mouth of the glass tube being 
meanwhile under water. If this does not 
force the egg out of the glass tube continue 
to hold the piston closed, squeeze the bulb 
with the right hand, and then with the in- 
dex finger press the little auxiliary piston 
at the end of the handle. If now the bulb 
is released it will fill. Removing then the 
pressure from the little piston on the han- 
dle there can be no escape of air at this 
point when the bulb is compressed, but only backward in the main tube, for 
the discharge outward is cut off by the closed lower piston valve. The egg will 
thus be forced out of the glass tube. 

Care should be taken to avoid drawing water into the bulb, but in such 
event a discharge may be effected by proceeding as just described except that 
the lower piston valve is in this case left open. 




-.Apparatus for cleaning hatching i 
troughs. 



1032 



BULI^ETIN OF THE BUREAU OF FISHERIES. 



as dip nets and even shovels, for cleaning. 



This apparatus has proved most successful and obviates the necessity of 
putting the hands in cold water to do the work of picking the eggs. 

A CLEANING DEVICE FOR PONDS OR AQUARIA. 

The imperfect construction of some ponds, not permitting them to be 
entirely emptied, necessitates the use of various means and implements, such 

With even the greatest care it is 
difficult to maintain the clean- 
liness necessary to avoid mor- 
tality among the fish. 

The present device enables 
the fish culturist to prevent dis- 
ease by more thorough cleaning, 
and also by avoiding the bruises 
inflicted upon the fish in the 
course of the ordinary cleaning 
process if the water is muddy. 
It also prevents the disagreeable 
taste of fish reared in muddy and 
ill-cleaned ponds. 

The apparatus is constructed 
upon the principle of the fore- 
going rubber siphon and glass 
tube. Being for larger work, 
however, it is made of brass pipe 
with rubber or canvas connec- 
tions. It consists of a main arm 
terminating in an elbow joint 
which is expanded into a flat tri- 
angular cavity with an entrance 
valve. This valve, opening up- 
ward, is controlled by a lever at- 
tached by a cord to a trigger on 
the handle of the apparatus. The handle, which is of wood and inserted in 
the upper end of the main tube, may be of any desired length. Branching off 
the main tube a short distance below the handle is an arm for connection with 
the discharge pipe. 

In operation the discharge arm may be attached to rubber or canvas hose, 
with outlet below the level in the pond or tank, and the apparatus guided about 
over the bottom by means of the handle, the suction being regulated by the 
cord attached to the valve. In cases where the pond may not be emptied. 




Fig. 4. — Cleaning device for ponds and aquaria 



DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



1033 



and the siphon therefore is not feasible, the handle is removed from the cleaning 
apparatus and a pump attached. A small suction pump, such as used in gardens, 
is very suitable. If for any cause convenient, the apparatus may be left in 
the pond, for with the valve closed the suction can not act. 

OXYGENATION AND VACUUM-PRODUCING APPARATUS. 

This apparatus is in effect a section which may be introduced into a supply 
pipe, and consists of an exhaust chamber and an air-supply tube, with the essen- 
tial feature of a movable jet. The differences of 
water pressure and sizes of supply pipes render a 
stationary jet ineffective or even useless at times. 

The model here represented has a jet of 5 to 6 
millimeters diameter, adjustable by means of a screw 
on the outside, and sends air into the water to a 
depth of about 4 meters, from an opening of 20 mil- 
limeters. It may be mounted with openings varying 
from 20 to 26 millimeters. The lower part of the 
apparatus is provided with a movable tube having 
a conical entrance, to divide the water better and 
make the vacuum stronger. 

The pressure of the water of the Vanne is dimin- 
ished in the sluices of the Trocadero Aquarium b}^ 
the many separate outflows, and to provide the de- 
sired currents, 13 of these oxygenators have been in- 
stalled. The fishes playing in the numerous silvery 
bubbles which rise from the bottom arouse much ad- 
miration from the public, and it will be readily be- 
lieved that the fish are clean and never sluggish. 
Small or large, they thrive with this kind of aera- 
tion, which brings them artificial currents of water 
which they did not find in these same ponds before. 
These currents, moreover, do not allow the food given 
to fall to the bottom when it is sprinkled in. The 
young fish, some 5 or 6 weeks old, may be seen to 
catch in passing the small particles of food which the 
water brings them. The ponds are from 2 to 3 meters 
deep, from 7 to 8 meters long, and from 2 to 3 meters 
wide. These oxygenators render great service; it is a hygienic method which 
ought to be used wherever possible. 

This apparatus may be used without disarrangement for the purpose of 
producing a vacuum in boxes specially prepared for the preservation of food 
for fishes and even for the shipment of fishes destined for market. It may be 




I034 BULLETIN OF THE BUREAU OF FISHERIES. 

of various sizes and may be placed at the base of a reservoir or even in a recepta- 
cle in an automobile for the transportation of fishes alive. In this case the 
motor will turn a small pump in the apparatus and this even during stops, with 
the exception of cases when the motor itself does not work. 

I have a small oxygenator at the extremity of a small hand pump, to serve 
me for long transportations. This is more practical than an air pump, the 
globules from which are too large and must be divided. By means of its water 
jet, which carries the air along, the oxygenator divides its globules, and these 
rising less rapidly to the surface, aerate the water much better than the large 
globules. 

The discharge pipe of the oxygenator must be sufficiently large to contain 
at the same time the air and the water which must pass through it together. 
Thus if it should be found necessary, as for instance, if the ponds need to be 
cleaned by flushing, it is possible to attach at the connection of the air pipe a 
joint identical with the water pipe and use this double water supply in spite of 
the presence of the oxygenator which might seem to intercept it. Or the spigot 
of the air pipe may be closed and the flow of water is then normal. 

Some three years ago I placed with a manufacturer a design for an oxy- 
genator, but feeling some distrust withheld the feature of the sliding jet, though 
I mentioned it. It was well that I did withhold it, for not only did I lose 
my apparatus but the idea was stolen, though I retained the secret of the true 
mode of operation. The sliding jet is indispensable to success. In a locality in 
the north of France a system of oxygenators installed at great expense afterwards 
necessitated the modification of a great part of the plumbing and changes in the 
size of jets, all of which is obviated by the sliding jet. 

SCRAPER FOR PREPARING FISH FOOD. 

Fish culturists know that it is not a very agreeable or easy task to extract 
the pulp from the spleen of horses or beeves, and that it is, moreover, a very long 
and fatiguing operation if a knife, spoon, or any such instrument is used. For 
my part, having some 1 5 kilograms and sometimes more of spleen to scrape, I 
endeavored to find a readier means. 

My device somewhat resembles a block plane in shape, with 5 blades pro- 
truding their full depth. I had to seek a long time for blades of requisite flexi- 
bility, shape, and size, and to fit them in proper place and at proper inclination. 
It will be seen that these blades have not all the same shape. This is because 
each has its definite place of contact, none scraping directly on the spot which 
the preceding blade has scraped. Otherwise the pulp would be immediately 
torn at the first stroke of the scraper. I have likewise overcome the other 
difficulties encountered at the beginning of the attempt at this device. 

The following is the mode of proceeding: 



DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



1035 



To a board, i meter long and 0.30 meter wide, edged with a strip 0.02 meter 
high to keep the pulp of the spleen from falling over the sides, is affixed at each 
end a transverse support to raise it above the surface of the table on which the 
scraper is used. One support should be sufficiently high to permit a small recep- 
tacle to be placed somewhat under the board, at a height of o.io meter approxi- 
mately, while for the other support a height of 0.03 meter would be sufficient. 
The board will thus be inclined. 

At the lower end a narrow board is attached fiat by means of a hinge at the 
farther side. This small board is 0.05 to 0.06 meter wide, of the same thickness 
as the big board, and in it are fixed 10 to 12 sharp points 0.02 meter long, spaced 
0.015 meter apart. This board 

_Boarcf 

C/smp 



swung back, the spleen is placed 
flat on the larger board, some 0.03 
or 0.04 meter of it falling over the 
end. The small board is then 
swung forward and its points, 
piercing the spleen, will keep the 
latter in place during the scrap- 
ing. A small hook at the end 
holds the small board in position 
to keep the spleen from slipping. 
The thin skin around the spleen is 
taken off with a knife and the 
spleen is cut longitudinally sev- 
eral times. 

The scraper is manipulated 
in the manner of a plane. The 
spleen should be turned end for 
end, if need be, to scrape the part 
which had been held under the 
toothed board. 



Cfamp 




-Scraper for preparing fish food. 



This implement may seem an odd device, but it is remarkable how rapidly 
the spleen pulp is extracted. Two to three minutes are sufficient for the opera- 
tion, with a spleen weighing 0.80 kilogram. It should be added that this pulp 
does not contain any remnants of spleen cells, as might be supposed. 

If the spleen is frozen in winter and it is not feared that the nutritive quali- 
ties of the raw flesh or the spleen pulp might be decreased, it may be immersed 
for a few minutes in hot water before being scraped and the operation will be 
still more rapid. 

Several establishments make use of this scraper because their proprietors 
have seen me use mine. I have ordered several from a manufacturing firm. 



